Method and eNB equipment for supporting seamless handover

A method performed by a second base station in a wireless communication system, the method comprising:

• receiving, from a first base station, a handover request message including information to request the second base station to add second information to a handover request acknowledge message;
• and
• transmitting, to the first base station, the handover request acknowledge message including the second information,
• wherein a radio resource control (RRC) connection reconfiguration message including the second information is transmitted to a user equipment (UE),
• wherein the handover request message includes the information based on first information included in a UE capability message, the first information indicating whether a connection between the first base station and the UE is maintained after a transmission of the RRC connection reconfiguration message before a first transmission on a random access channel (RACH) from the UE to the second base station is performed, and
• wherein the second information indicates whether the UE continues a downlink reception or an uplink transmission with the first base station after the transmission of the RRC connection reconfiguration message before the first transmission on the RACH.

A method performed by a user equipment (UE) in a wireless communication system, the method comprising:

• transmitting, to a first base station, UE capability information including first information;
• and
• receiving, from the first base station, a radio resource control (RRC) connection reconfiguration message including second information,
• wherein the first information indicates whether a connection between the first base station and the UE is maintained after a transmission of the RRC connection reconfiguration message before a first transmission on a random access channel (RACH) from the UE to a second base station is performed,
• wherein the second information indicates whether the UE continues a downlink reception or an uplink transmission with the first base station after the transmission of the RRC connection reconfiguration message before the first transmission on the RACH,
• wherein the RRC connection reconfiguration message is received after a handover request message including information to request the second base station to add the second information to a handover request acknowledge message is transmitted from the first base station to the second base station, and
• wherein the handover request acknowledge message including the second information is transmitted from the second base station to the first base station.

A first base station in a wireless communication system, the first base station comprising:

• a transceiver;
• and
• a controller configured to:
• receive, from a user equipment (UE) via the transceiver, UE capability information including first information,
• transmit, to a second base station via the transceiver, a handover request message including information to request the second base station to add second information to handover request acknowledge message;
• receive, from the second base station via the transceiver, the handover request acknowledge message including the second information;
• and
• transmit, to the UE via the transceiver, a radio resource control (RRC) connection reconfiguration message including the second information,
• wherein the first information indicates whether a connection between the first base station and the UE is maintained after a transmission of the RRC connection reconfiguration message before a first transmission on a random access channel (RACH) from the UE to the second base station is performed, and
• wherein the second information indicates whether the UE continues a downlink reception or an uplink transmission with the first base station after the transmission of the RRC connection reconfiguration message before the first transmission on the RACH.

A second base station in a wireless communication system, the second base station comprising:

• a transceiver;
• and
• a controller configured to:
• receive, from a first base station via the transceiver, a handover request message including information to request the second base station to add second information to a handover request acknowledge message,
• transmit, to the first base station via the transceiver, the handover request acknowledge message including the second information,
• wherein a radio resource control (RRC) connection reconfiguration message including the second information is transmitted to a user equipment (UE),
• wherein the handover request message includes the information based on first information included in a UE capability message, the first information indicating whether a connection between the first base station and the UE is maintained after a transmission of the RRC connection reconfiguration message before a first transmission on a random access channel (RACH) from the UE to the second base station is performed, and
• wherein the second information indicates whether the UE continues a downlink reception or an uplink transmission with the first base station after the transmission of the RRC connection reconfiguration message before the first transmission on the RACH.

A user equipment (UE) in a wireless communication system, the UE comprising:

• a transceiver;
• and
• a controller configured to:
• transmit, to a first base station via the transceiver, UE capability information including first information;
• and
• receive, from the first base station via the transceiver, a radio resource control (RRC) connection reconfiguration message including second information,
• wherein the first information indicates whether a connection between the first base station and the UE is maintained after a transmission of the RRC connection reconfiguration message before a first transmission on a random access channel (RACH) from the UE to a second base station is performed,
• wherein the second information indicates whether the UE continues a downlink reception or an uplink transmission with the first base station after the transmission of the RRC connection reconfiguration message before the first transmission on the RACH,
• wherein the RRC connection reconfiguration message is received after a handover request message including information to request the second base station to add the second information to a handover request acknowledge message is transmitted from the first base station to the second base station, and
• wherein the handover request acknowledge message including the second information is transmitted from the second base station to the first base station.